Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

bpo-46219, 46221: simplify except* implementation following exc_info changes. Move helpers to exceptions.c. Do not assume that exception groups are truthy. (GH-30289)

This commit is contained in:
Irit Katriel 2022-01-02 23:22:42 +00:00 committed by GitHub
parent 8e75c6b49b
commit 65e7c1f90e
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
9 changed files with 179 additions and 149 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
.github/CODEOWNERS vendored
View File

@ -21,6 +21,14 @@ Python/ceval.c @markshannon
Python/compile.c @markshannon
Python/ast_opt.c @isidentical
# Exceptions
Lib/traceback.py @iritkatriel
Lib/test/test_except*.py @iritkatriel
Lib/test/test_traceback.py @iritkatriel
Objects/exceptions.c @iritkatriel
Python/traceback.c @iritkatriel
Python/pythonrun.c @iritkatriel
# Hashing
**/*hashlib* @python/crypto-team @tiran
**/*pyhash* @python/crypto-team @tiran

4
Doc/library/dis.rst
View File

@ -911,8 +911,8 @@ All of the following opcodes use their arguments.
Combines the raised and reraised exceptions list from TOS, into an exception
group to propagate from a try-except* block. Uses the original exception
group from TOS1 to reconstruct the structure of reraised exceptions. Pops
two items from the stack and pushes 0 (for lasti, which is unused) followed
by the exception to reraise or ``None`` if there isn't one.
two items from the stack and pushes the exception to reraise or ``None``
if there isn't one.
.. versionadded:: 3.11

6
Include/internal/pycore_pyerrors.h
View File

@ -87,9 +87,9 @@ PyAPI_FUNC(PyObject *) _PyExc_CreateExceptionGroup(
const char *msg,
PyObject *excs);
PyAPI_FUNC(PyObject *) _PyExc_ExceptionGroupProjection(
PyObject *left,
PyObject *right);
PyAPI_FUNC(PyObject *) _PyExc_PrepReraiseStar(
PyObject *orig,
PyObject *excs);
PyAPI_FUNC(int) _PyErr_CheckSignalsTstate(PyThreadState *tstate);

3
Lib/importlib/_bootstrap_external.py
View File

@ -375,6 +375,7 @@ _code_type = type(_write_atomic.__code__)
# Python 3.11a4 3467 (Change CALL_xxx opcodes)
# Python 3.11a4 3468 (Add SEND opcode)
# Python 3.11a4 3469 (bpo-45711: remove type, traceback from exc_info)
# Python 3.11a4 3470 (bpo-46221: PREP_RERAISE_STAR no longer pushes lasti)
#
# MAGIC must change whenever the bytecode emitted by the compiler may no
@ -384,7 +385,7 @@ _code_type = type(_write_atomic.__code__)
# Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
# in PC/launcher.c must also be updated.
MAGIC_NUMBER = (3469).to_bytes(2, 'little') + b'\r\n'
MAGIC_NUMBER = (3470).to_bytes(2, 'little') + b'\r\n'
_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c
_PYCACHE = '__pycache__'

28
Lib/test/test_except_star.py
View File

@ -952,6 +952,34 @@ class TestExceptStarExceptionGroupSubclass(ExceptStarTest):
self.assertEqual(teg.code, 42)
self.assertEqual(teg.exceptions[0].code, 101)
def test_falsy_exception_group_subclass(self):
class FalsyEG(ExceptionGroup):
def __bool__(self):
return False
def derive(self, excs):
return FalsyEG(self.message, excs)
try:
try:
raise FalsyEG("eg", [TypeError(1), ValueError(2)])
except *TypeError as e:
tes = e
raise
except *ValueError as e:
ves = e
pass
except Exception as e:
exc = e
for e in [tes, ves, exc]:
self.assertFalse(e)
self.assertIsInstance(e, FalsyEG)
self.assertExceptionIsLike(exc, FalsyEG("eg", [TypeError(1)]))
self.assertExceptionIsLike(tes, FalsyEG("eg", [TypeError(1)]))
self.assertExceptionIsLike(ves, FalsyEG("eg", [ValueError(2)]))
class TestExceptStarCleanup(ExceptStarTest):
def test_exc_info_restored(self):

1
Misc/NEWS.d/next/Core and Builtins/2022-01-01-14-23-57.bpo-46221.7oGp-I.rst Normal file
View File

@ -0,0 +1 @@
:opcode:`PREP_RERAISE_STAR` no longer pushes ``lasti`` to the stack.

120
Objects/exceptions.c
View File

@ -1207,8 +1207,8 @@ collect_exception_group_leaves(PyObject *exc, PyObject *leaves)
* of eg which contains all leaf exceptions that are contained
* in any exception group in keep.
*/
PyObject *
_PyExc_ExceptionGroupProjection(PyObject *eg, PyObject *keep)
static PyObject *
exception_group_projection(PyObject *eg, PyObject *keep)
{
assert(_PyBaseExceptionGroup_Check(eg));
assert(PyList_CheckExact(keep));
@ -1245,6 +1245,122 @@ _PyExc_ExceptionGroupProjection(PyObject *eg, PyObject *keep)
return result;
}
static bool
is_same_exception_metadata(PyObject *exc1, PyObject *exc2)
{
assert(PyExceptionInstance_Check(exc1));
assert(PyExceptionInstance_Check(exc2));
PyBaseExceptionObject *e1 = (PyBaseExceptionObject *)exc1;
PyBaseExceptionObject *e2 = (PyBaseExceptionObject *)exc2;
return (e1->note == e2->note &&
e1->traceback == e2->traceback &&
e1->cause == e2->cause &&
e1->context == e2->context);
}
/*
This function is used by the interpreter to calculate
the exception group to be raised at the end of a
try-except* construct.
orig: the original except that was caught.
excs: a list of exceptions that were raised/reraised
in the except* clauses.
Calculates an exception group to raise. It contains
all exceptions in excs, where those that were reraised
have same nesting structure as in orig, and those that
were raised (if any) are added as siblings in a new EG.
Returns NULL and sets an exception on failure.
*/
PyObject *
_PyExc_PrepReraiseStar(PyObject *orig, PyObject *excs)
{
assert(PyExceptionInstance_Check(orig));
assert(PyList_Check(excs));
Py_ssize_t numexcs = PyList_GET_SIZE(excs);
if (numexcs == 0) {
return Py_NewRef(Py_None);
}
if (!_PyBaseExceptionGroup_Check(orig)) {
/* a naked exception was caught and wrapped. Only one except* clause
* could have executed,so there is at most one exception to raise.
*/
assert(numexcs == 1 || (numexcs == 2 && PyList_GET_ITEM(excs, 1) == Py_None));
PyObject *e = PyList_GET_ITEM(excs, 0);
assert(e != NULL);
return Py_NewRef(e);
}
PyObject *raised_list = PyList_New(0);
if (raised_list == NULL) {
return NULL;
}
PyObject* reraised_list = PyList_New(0);
if (reraised_list == NULL) {
Py_DECREF(raised_list);
return NULL;
}
/* Now we are holding refs to raised_list and reraised_list */
PyObject *result = NULL;
/* Split excs into raised and reraised by comparing metadata with orig */
for (Py_ssize_t i = 0; i < numexcs; i++) {
PyObject *e = PyList_GET_ITEM(excs, i);
assert(e != NULL);
if (Py_IsNone(e)) {
continue;
}
bool is_reraise = is_same_exception_metadata(e, orig);
PyObject *append_list = is_reraise ? reraised_list : raised_list;
if (PyList_Append(append_list, e) < 0) {
goto done;
}
}
PyObject *reraised_eg = exception_group_projection(orig, reraised_list);
if (reraised_eg == NULL) {
goto done;
}
if (!Py_IsNone(reraised_eg)) {
assert(is_same_exception_metadata(reraised_eg, orig));
}
Py_ssize_t num_raised = PyList_GET_SIZE(raised_list);
if (num_raised == 0) {
result = reraised_eg;
}
else if (num_raised > 0) {
int res = 0;
if (!Py_IsNone(reraised_eg)) {
res = PyList_Append(raised_list, reraised_eg);
}
Py_DECREF(reraised_eg);
if (res < 0) {
goto done;
}
result = _PyExc_CreateExceptionGroup("", raised_list);
if (result == NULL) {
goto done;
}
}
done:
Py_XDECREF(raised_list);
Py_XDECREF(reraised_list);
return result;
}
static PyMemberDef BaseExceptionGroup_members[] = {
{"message", T_OBJECT, offsetof(PyBaseExceptionGroupObject, msg), READONLY,
PyDoc_STR("exception message")},

133
Python/ceval.c
View File

@ -1092,7 +1092,6 @@ fail:
static int do_raise(PyThreadState *tstate, PyObject *exc, PyObject *cause);
static PyObject *do_reraise_star(PyObject *excs, PyObject *orig);
static int exception_group_match(
PyObject* exc_value, PyObject *match_type,
PyObject **match, PyObject **rest);
@ -2777,7 +2776,7 @@ check_eval_breaker:
assert(PyList_Check(excs));
PyObject *orig = POP();
PyObject *val = do_reraise_star(excs, orig);
PyObject *val = _PyExc_PrepReraiseStar(orig, excs);
Py_DECREF(excs);
Py_DECREF(orig);
@ -2785,8 +2784,6 @@ check_eval_breaker:
goto error;
}
PyObject *lasti_unused = Py_NewRef(_PyLong_GetZero());
PUSH(lasti_unused);
PUSH(val);
DISPATCH();
}
@ -6313,134 +6310,6 @@ exception_group_match(PyObject* exc_value, PyObject *match_type,
return 0;
}
/* Logic for the final raise/reraise of a try-except* contruct
(too complicated for inlining).
*/
static bool
is_same_exception_metadata(PyObject *exc1, PyObject *exc2)
{
assert(PyExceptionInstance_Check(exc1));
assert(PyExceptionInstance_Check(exc2));
PyObject *tb1 = PyException_GetTraceback(exc1);
PyObject *ctx1 = PyException_GetContext(exc1);
PyObject *cause1 = PyException_GetCause(exc1);
PyObject *tb2 = PyException_GetTraceback(exc2);
PyObject *ctx2 = PyException_GetContext(exc2);
PyObject *cause2 = PyException_GetCause(exc2);
bool result = (Py_Is(tb1, tb2) &&
Py_Is(ctx1, ctx2) &&
Py_Is(cause1, cause2));
Py_XDECREF(tb1);
Py_XDECREF(ctx1);
Py_XDECREF(cause1);
Py_XDECREF(tb2);
Py_XDECREF(ctx2);
Py_XDECREF(cause2);
return result;
}
/*
excs: a list of exceptions to raise/reraise
orig: the original except that was caught
Calculates an exception group to raise. It contains
all exceptions in excs, where those that were reraised
have same nesting structure as in orig, and those that
were raised (if any) are added as siblings in a new EG.
Returns NULL and sets an exception on failure.
*/
static PyObject *
do_reraise_star(PyObject *excs, PyObject *orig)
{
assert(PyList_Check(excs));
assert(PyExceptionInstance_Check(orig));
Py_ssize_t numexcs = PyList_GET_SIZE(excs);
if (numexcs == 0) {
return Py_NewRef(Py_None);
}
if (!_PyBaseExceptionGroup_Check(orig)) {
/* a naked exception was caught and wrapped. Only one except* clause
* could have executed,so there is at most one exception to raise.
*/
assert(numexcs == 1 || (numexcs == 2 && PyList_GET_ITEM(excs, 1) == Py_None));
PyObject *e = PyList_GET_ITEM(excs, 0);
assert(e != NULL);
return Py_NewRef(e);
}
PyObject *raised_list = PyList_New(0);
if (raised_list == NULL) {
return NULL;
}
PyObject* reraised_list = PyList_New(0);
if (reraised_list == NULL) {
Py_DECREF(raised_list);
return NULL;
}
/* Now we are holding refs to raised_list and reraised_list */
PyObject *result = NULL;
/* Split excs into raised and reraised by comparing metadata with orig */
for (Py_ssize_t i = 0; i < numexcs; i++) {
PyObject *e = PyList_GET_ITEM(excs, i);
assert(e != NULL);
if (Py_IsNone(e)) {
continue;
}
bool is_reraise = is_same_exception_metadata(e, orig);
PyObject *append_list = is_reraise ? reraised_list : raised_list;
if (PyList_Append(append_list, e) < 0) {
goto done;
}
}
PyObject *reraised_eg = _PyExc_ExceptionGroupProjection(orig, reraised_list);
if (reraised_eg == NULL) {
goto done;
}
if (!Py_IsNone(reraised_eg)) {
assert(is_same_exception_metadata(reraised_eg, orig));
}
Py_ssize_t num_raised = PyList_GET_SIZE(raised_list);
if (num_raised == 0) {
result = reraised_eg;
}
else if (num_raised > 0) {
int res = 0;
if (!Py_IsNone(reraised_eg)) {
res = PyList_Append(raised_list, reraised_eg);
}
Py_DECREF(reraised_eg);
if (res < 0) {
goto done;
}
result = _PyExc_CreateExceptionGroup("", raised_list);
if (result == NULL) {
goto done;
}
}
done:
Py_XDECREF(raised_list);
Py_XDECREF(reraised_list);
return result;
}
/* Iterate v argcnt times and store the results on the stack (via decreasing
sp). Return 1 for success, 0 if error.

25
Python/compile.c
View File

@ -1134,7 +1134,7 @@ stack_effect(int opcode, int oparg, int jump)
return jump ? 1 : 0;
case PREP_RERAISE_STAR:
return 0;
return -1;
case RERAISE:
return -1;
case PUSH_EXC_INFO:
@ -3488,12 +3488,16 @@ compiler_try_except(struct compiler *c, stmt_ty s)
[orig, res, rest] Ln+1: LIST_APPEND 1 ) add unhandled exc to res (could be None)
[orig, res] PREP_RERAISE_STAR
[i, exc] POP_JUMP_IF_TRUE RER
[i, exc] POP
[i] POP
[exc] DUP_TOP
[exc, exc] LOAD_CONST None
[exc, exc, None] COMPARE_IS
[exc, is_none] POP_JUMP_IF_FALSE RER
[exc] POP_TOP
[] JUMP_FORWARD L0
[i, exc] RER: POP_EXCEPT_AND_RERAISE
[exc] RER: ROT_TWO
[exc, prev_exc_info] POP_EXCEPT
[exc] RERAISE 0
[] L0: <next statement>
*/
@ -3657,18 +3661,21 @@ compiler_try_star_except(struct compiler *c, stmt_ty s)
compiler_use_next_block(c, reraise_star);
ADDOP(c, PREP_RERAISE_STAR);
ADDOP(c, DUP_TOP);
ADDOP_JUMP(c, POP_JUMP_IF_TRUE, reraise);
ADDOP_LOAD_CONST(c, Py_None);
ADDOP_COMPARE(c, Is);
ADDOP_JUMP(c, POP_JUMP_IF_FALSE, reraise);
NEXT_BLOCK(c);
/* Nothing to reraise - pop it */
ADDOP(c, POP_TOP);
/* Nothing to reraise */
ADDOP(c, POP_TOP);
ADDOP(c, POP_BLOCK);
ADDOP(c, POP_EXCEPT);
ADDOP_JUMP(c, JUMP_FORWARD, end);
compiler_use_next_block(c, reraise);
ADDOP(c, POP_BLOCK);
ADDOP(c, POP_EXCEPT_AND_RERAISE);
ADDOP(c, ROT_TWO);
ADDOP(c, POP_EXCEPT);
ADDOP_I(c, RERAISE, 0);
compiler_use_next_block(c, cleanup);
ADDOP(c, POP_EXCEPT_AND_RERAISE);
compiler_use_next_block(c, orelse);